Multiple autonomic and repolarization investigation of sudden cardiac death in dilated cardiomyopathy and controls

Circ Arrhythm Electrophysiol. 2014 Dec;7(6):1101-8. doi: 10.1161/CIRCEP.114.001745. Epub 2014 Sep 27.


Background: Prophylactic defibrillator implantation is recommended in dilated, nonischemic heart disease and left ventricular ejection fraction of ≤0.30 to 0.35. Noninvasive testing should improve accuracy in decision making of prophylactic defibrillator implantation.

Methods and results: We enrolled 60 patients (median age, 57 years) with dilated cardiomyopathy and left ventricular ejection fraction ≤0.50, and 30 control subjects (median age, 59 years) with left ventricular ejection fraction >0.50. The protocol included an initial assessment, a second assessment after 3 years, and a final follow-up: pharmacological baroreflex testing (baroreceptor reflex sensitivity), short-term spectral analysis of heart rate variability (low frequency/high frequency), and long-term time domain analysis (SD of all normal-to-normal R-R intervals), exercise microvolt T wave alternans, and signal-averaged ECG, and corrected QT-time. The median follow-up was 7 years. End points were cardiac death, resuscitated cardiac arrest, and arrhythmic death. Cardiac death was observed in 21 patients. Resuscitated cardiac arrest and arrhythmic death caused by ventricular tachyarrhythmias ≥240 per minute was observed in 7 and 10 patients, respectively. In the single time point analysis, microvolt T wave alternans, baroreceptor reflex sensitivity, and SD of all normal-to-normal R-R intervals at initial testing added significant information regarding cardiac death. Microvolt T wave alternans added information on resuscitated cardiac arrest or arrhythmic death at multiple time points (P<0.001). False-negative microvolt T wave alternans results were seen in 8% of patients.

Conclusions: Noninvasive testing and left ventricular ejection fraction could not reliably identify patients with dilated cardiomyopathy at risk of fatal ventricular tachyarrhythmias. Therefore, the strategy to confine prophylactic implantable cardioverter-defibrillator implantation to patients with dilated cardiomyopathy and severely reduced LV function should be reconsidered.

Keywords: (non-invasive) risk stratification; cardiomyopathy; dilated; implantable cardioverter defibrillator; sudden cardiac death or arrhythmic death.

Publication types

  • Observational Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Autonomic Nervous System / physiopathology*
  • Baroreflex*
  • Blood Pressure
  • Cardiomyopathy, Dilated / complications
  • Cardiomyopathy, Dilated / diagnosis*
  • Cardiomyopathy, Dilated / mortality*
  • Cardiomyopathy, Dilated / physiopathology
  • Cardiomyopathy, Dilated / therapy
  • Case-Control Studies
  • Death, Sudden, Cardiac / etiology*
  • Death, Sudden, Cardiac / prevention & control
  • Decision Support Techniques*
  • Defibrillators, Implantable
  • Electric Countershock / instrumentation
  • Electrocardiography
  • Female
  • Heart Rate
  • Humans
  • Male
  • Middle Aged
  • Patient Selection
  • Predictive Value of Tests
  • Primary Prevention / instrumentation
  • Prospective Studies
  • Risk Assessment
  • Risk Factors
  • Stroke Volume*
  • Time Factors
  • Ventricular Function, Left*
  • Young Adult